Following deregulation of the telephone industry decades ago, it became standard practice to provide a test interface at the premises of a telephone subscriber. A standardized form of such test interface includes a receptacle or jack of the RJ-11 type connected to the telephone company's line (or "incoming line") and a plug carried by a short length of wire connected to the subscriber's line. Ordinarily, the plug is received in the jack, to provide the subscriber with telephone service. If trouble should develop, the subscriber's-line plug is removed from the jack and the plug of a test telephone that is in proper working condition is inserted into the jack. Normal operation of the test telephone shows that the fault is not in the incoming line and that, therefore, the fault is in the subscriber's line. Following the test, ordinarily after the fault has been rectified, the subscriber's-line plug is again inserted into the jack, restoring service. Where many telephone subscribers are grouped at a common location, typically at an apartment house, a panel has commonly been provided having a test interface for each subscriber. Each test interface includes a jack having contacts that are connected to the incoming line corresponding to the subscriber. The usual plug of the test interface (see above) that is connected to the subscriber's line is received in the jack; it is to be removed by a subscriber in performing a fault-locating test.
Each test jack has been provided with its own padlocked cover so that a stranger is prevented from using any of the test interface jacks to pilfer service. However, multiple-subscriber panels include some provision for assuring access by telephone company personnel to the wiring and components underlying the individually padlocked covers.
In the standardized form of test interface discussed above, the wired plug that is connected to the subscriber's line is frequently damaged. With no thought to eliminating that wired plug, attention has been devoted, instead, to making the wired plug more rugged and easily replaced, as evidenced by U.S. Pat. No. 5,004,433. The wired plug connected to the subscriber's line in panels having test jacks continues in widespread use.
A deviation from that practice is disclosed in U.S. Pat. No. 5,292,199. In the '199 patent, test interface jacks are provided with incoming line contacts; access to those jacks is limited by individually padlocked covers, and each jack also contains contacts connected to the subscriber's line. Avoiding the wired plug of the usual test interface, each cover in the '199 patent bears bridging contacts that complete the connection of the subscriber line to the incoming line when and as long as the cover is closed. When the cover is opened, the bridging contacts are carried away from the jack of the test interface; the jack is then available for a plug of a test device to be inserted.
The standard RJ-11 test interface jack is used in the '199 patent. The bridging contacts are carried by the covers, so that the form of cover that is used must be inherently rugged and precise, in order to carry the bridging contacts to the required positions in the miniature RJ-11 jack.
U.S. Pat. No. 5,291,553 issued Mar. 1, 1994 to Smith, discusses a telephone service panel of assembled stand-alone modules. Each module has a switching receptacle of the RJ-11 style that avoids dependence on a wired subscriber plug that characterizes the more widely known telephone service panels.